Sunday, 25 March 2012

There are many types of virtualization- server, network, storage, and more.
In this article, we will demystify these complex terms, explain what they can do
for you, and name specific products that provide these functions. So prepare for
the smoke to be cleared...

Monitoring Both
Physical & Virtual Servers from One ConsoleAre you able to identify precisely which processes are sucking up resources
and slowing down your servers? Can you do this equally well over VM guests that
VMotion?

OpManager also allows admins to remotely shut down
problem-causing processes. With over 500 built-in monitors & 70 deep VMware
metrics reported on, OpManager is one of the most comprehensive fault &
performance management solutions available today for entire server
infrastructure - both physical and virtual.

What is Server Virtualization?

Out of all three of the different types of virtualization discussed in this
article, I believe that server virtualization is the type of virtualization you
are most familiar with. When people say "virtualization", they are usually
referring to server virtualization. However, they should really clarify what
type of virtualization they are talking about because there are multiple
types.
The Wikipedia
defines virtualization as "a broad term that refers to the abstraction of
computer resources". Another definition, also from Wikipedia is "a technique for
hiding the physical characteristics of computing resources from the way in which
other systems, applications, or end users interact with those resources".
With those definitions as our background, what is server virtualization?
Simply put, server virtualization software allows you to run multiple guest
computers on a single host computer with those guest computers believing they
are running on their own hardware. By doing this, you gain all the benefits of
any type of virtualization: portability of guest virtual machines, reduced
operating costs, reduced administrative overhead, server consolidation, testing
& training, disaster recovery benefits, and more.
Examples of server virtualization products are:

VMware Server, Workstation, Player, and ESX Server

Microsoft Virtual PC and Virtual Server

Xen

Virtual Iron

And more

That said, different products provide different levels of virtualization.
There are:

full virtualization - guest OS is unmodified and believes
it is running on the same hardware as the host OS

para virtualization - guest OS is modified, as with
Xen

emulation - guest OS is unmodified but it is running on a
software emulated CPU

There is no doubt that server virtualization is the wave of the future.
Consider these facts:

A 2007 Forrester Research
study found that 40% of businesses are using server virtualization. Of those
40%, 50% of those are using VMware products and 9% are using Microsoft.

Microsoft will be including Server Virtualization as part of the next
release of the Windows Server operating system, codename Viridian.

Cisco has announced a strategic
investment in VMware and Cisco has stated that they believe that
virtualization (across the board) is the future of computing. Cisco has made
virtualization part of their Data Center 3.0
strategy.

Microsoft will make the Windows Server 2008 virtualization software "Xen-Friendly"

Here is what Server Virtualization looks like:

What is Network Virtualization?

When I first heard of network virtualization, I thought of VLANs. I thought,
"don't we already have network virtualization when we use VLANs?" I mean, a VLAN
is a "virtual LAN", which sounds like a virtual network to me. While this logic
makes sense, there is much more to network virtualization than just VLANs.
Like these other forms of virtualization, network virtualization is not that
new. Sun and HP have been talking about network virtualization for years. Now,
Cisco
has picked up the network virtualization ball and run with it. They are
touting NV as the next big thing and as an integral part of their Data Center
3.0 strategy.
What does network virtualization do? The theory behind network virtualization
is to take many of the of the traditional client/server based services and put
them "on the network". To Cisco, this means making routing and switches perform
more services. Cisco says that the 3 parts of network virtualization are:
access-control, path isolation, and service edge. This can be ambiguous when you
first read about it but Cisco
has a nice diagram that lays it all out to better visualize what it can do
for you. As you can see from the diagram, inside Cisco's routers and switches
you would find services like security, storage, VoIP, mobility, and application
delivery. To Cisco, it is their strategy to continue generating revenue from
their strong network infrastructure offerings. To me, this just helps to
increase the value of your network devices and leverage the network
infrastructure that is already required.

Another network vendor actually has,
in my opinion, a stronger network virtualization initiative than Cisco. That
company is 3Com. While 3Com is the equivalent of "David" to Cisco as "Goliath",
3Com actually has a working card that is inserted into a router. On that card is
a fully-functioning Linux server that has a connection to the backbone of the
router. On that Linux server, you can install applications like packet sniffers,
VoIP, Security applications, and many more. In the future, it is planned to be
able to run VMware on that Linux card so that you could, conceivably, run
Windows Servers. 3Com's open-source network virtualization initiative is called
3Com ON, or open-network.
Network virtualization is still in its early stages and it is too soon to
really say what it will or won't do for IT Pros like you and I.

What is Storage Virtualization?

Recently, I attended a conference on storage virtualization. The main
presenter was Datacore. They have
some fascinating products but they aren't the only storage virtualization
products available. However, they may be one of the more reasonably priced.
So what is Storage Virtualization (SV)? Again, like network virtualization,
when I first heard about storage virtualization, I thought that if I had a SAN,
I was already doing it. However, like network virtualization, there is more to
it than that. Wikipedia defines storage virtualization is "the abstraction at
any layer in the storage software and hardware stack.". This is what a SAN can
do, in general, but there are many more features that SV can bring you.
Let's look at an example. In most data centers, you only use a small
percentage of your storage because, even with a SAN, you have to allocate a full
disk LUN to the server (or servers) attaching to that LUN. Say that that LUN
fills up but you have disk space available on another LUN. It is very difficult
to take disk space away from one LUN and give it to another LUN. Plus, it is
very difficult to mix and match storage and make it appear all as one. Storage
virtualization works great for mirroring traffic across a WAN and for migrating
LUNs from one disk array to another without downtime.. Additionally, you can
perform thin-provisioning with SV where you can create new LUNs for new servers
but you over allocate the disk space on the server, compared to what the SAN is
really configured with. Say, for instance, the Windows server disk manager
thinks that you have 500GB allocated but, really, you only allocated 1GB. While
the utilization may grow to 6GB when Windows is installed, lets say that you
never grow the server beyond that. You have just saved 494GB of disk space but
you still have the flexibility to grow your data on that LUN without doing
anything else.

Summary

In summary, the Virtualization creates "virtually" an unlimited number of
possibilities for system administrators. The trouble with it, is being able to
understand the different types of virtualization, what they offer, and how they
an help you. To aid in your understanding, here is a quick summarization: